I’m left-handed and growing up, in school, there were never enough left handed scissors between myself and the maybe two other lefties in my class so I would often need to use right-handed scissors. But they would either not cut paper at all or kind of tear the paper, forcing me to switch to my right hand to get the scissors to cut smoothly.
Just yesterday I needed to trim a label and no matter how I angled the scissors, they would not cut the paper but they immediately did once I switched to my right hand. Thus, how do scissors “know” which hand you’re holding them in?
In: 2488
Your hands are mirror images of each other but they are not superimposable.
A ball pretty much is symmetric in all ways; you can rotate it freely or mirror it and it looks the same. A cube has a bunch of ways it can be symmetric, though you can only rotate it by certain angles for it to look the same. If you start painting faces (or otherwise making a part not identical) then you start getting limited in ways you can rotate or mirror it. Paint one side and you can rotate it on an axis through that face. Paint two different colors next to each other and you can still mirror it. Paint three adjacent ones with different colors and mirroring or rotating start resulting in different things, and there is no way to rotate and mirror to get an equivalent. Looking from the corner it would be the colors clockwise or counterclockwise.
For your hands, you can think of gloves. Ambidextrous are mirrored front to back so it doesn’t matter if your palm or the back of your hand. But other gloves match right and left; they have handedness. If you grip a rod with your thumb going one way, your fingers curl differently with respect that rod.
Right and left-handed scissors are mirror images of each other, and the relative orientation of the blades is different, kind of twisted in opposite directions to match the natural twisting force when using them.
This comes up pretty soon in organic chemistry, because carbon can make four bonds, and mirror-image compounds aren’t always interchangeable. For example, certain drugs only work for one ‘handedness’ of a molecule.
Your hands are mirror images of each other but they are not superimposable.
A ball pretty much is symmetric in all ways; you can rotate it freely or mirror it and it looks the same. A cube has a bunch of ways it can be symmetric, though you can only rotate it by certain angles for it to look the same. If you start painting faces (or otherwise making a part not identical) then you start getting limited in ways you can rotate or mirror it. Paint one side and you can rotate it on an axis through that face. Paint two different colors next to each other and you can still mirror it. Paint three adjacent ones with different colors and mirroring or rotating start resulting in different things, and there is no way to rotate and mirror to get an equivalent. Looking from the corner it would be the colors clockwise or counterclockwise.
For your hands, you can think of gloves. Ambidextrous are mirrored front to back so it doesn’t matter if your palm or the back of your hand. But other gloves match right and left; they have handedness. If you grip a rod with your thumb going one way, your fingers curl differently with respect that rod.
Right and left-handed scissors are mirror images of each other, and the relative orientation of the blades is different, kind of twisted in opposite directions to match the natural twisting force when using them.
This comes up pretty soon in organic chemistry, because carbon can make four bonds, and mirror-image compounds aren’t always interchangeable. For example, certain drugs only work for one ‘handedness’ of a molecule.
Try the scissors in both hands, opening them and closing them. Pay close attention to the blades: you will see that, in the right hand, the closing pressure pushes the two edges together.
Now, study the shape of the handles. You’ll see that there’s a bevel, or curvature, that makes this happen – but only in the right hand.
Tip: when you’re buying scissors, look at those handles. Those that are symmetrical will suit you better. Or shop professionally, with vendors who cater to the hair stylist or seamstress markets: you’ll find left-handed scissors. They will be expensive.
(Life-long lefty, here. I just use scissors in my right hand.)
Try the scissors in both hands, opening them and closing them. Pay close attention to the blades: you will see that, in the right hand, the closing pressure pushes the two edges together.
Now, study the shape of the handles. You’ll see that there’s a bevel, or curvature, that makes this happen – but only in the right hand.
Tip: when you’re buying scissors, look at those handles. Those that are symmetrical will suit you better. Or shop professionally, with vendors who cater to the hair stylist or seamstress markets: you’ll find left-handed scissors. They will be expensive.
(Life-long lefty, here. I just use scissors in my right hand.)
Try the scissors in both hands, opening them and closing them. Pay close attention to the blades: you will see that, in the right hand, the closing pressure pushes the two edges together.
Now, study the shape of the handles. You’ll see that there’s a bevel, or curvature, that makes this happen – but only in the right hand.
Tip: when you’re buying scissors, look at those handles. Those that are symmetrical will suit you better. Or shop professionally, with vendors who cater to the hair stylist or seamstress markets: you’ll find left-handed scissors. They will be expensive.
(Life-long lefty, here. I just use scissors in my right hand.)
It mostly about where your thumb is putting the pressure – correctly held your thumb is putting pressure that pushes the blades closer together and makes a smoother cut.
Incorrectly held (left holding right handed it pushes the blade further apart making it harder to cut,
Lefties can learn to use right handed scissors with a different grip. Ive always looped my thumb in and used my thumb to push the top blade in the opposite direction it normally would.
Nicer scissors are tight enough not to have that problem at all – always get the good ones. Its weird as an adult in the office…there is definitely the “good scissors”(the orange hand one with thick blades) and the “good staplers”(those metal once with some felt) that everyone wants to have and you have to be protective off lol.
It mostly about where your thumb is putting the pressure – correctly held your thumb is putting pressure that pushes the blades closer together and makes a smoother cut.
Incorrectly held (left holding right handed it pushes the blade further apart making it harder to cut,
Lefties can learn to use right handed scissors with a different grip. Ive always looped my thumb in and used my thumb to push the top blade in the opposite direction it normally would.
Nicer scissors are tight enough not to have that problem at all – always get the good ones. Its weird as an adult in the office…there is definitely the “good scissors”(the orange hand one with thick blades) and the “good staplers”(those metal once with some felt) that everyone wants to have and you have to be protective off lol.
It mostly about where your thumb is putting the pressure – correctly held your thumb is putting pressure that pushes the blades closer together and makes a smoother cut.
Incorrectly held (left holding right handed it pushes the blade further apart making it harder to cut,
Lefties can learn to use right handed scissors with a different grip. Ive always looped my thumb in and used my thumb to push the top blade in the opposite direction it normally would.
Nicer scissors are tight enough not to have that problem at all – always get the good ones. Its weird as an adult in the office…there is definitely the “good scissors”(the orange hand one with thick blades) and the “good staplers”(those metal once with some felt) that everyone wants to have and you have to be protective off lol.
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